What methods can be used in PHP to determine the number of days in each month for a calendar plugin?

To determine the number of days in each month for a calendar plugin in PHP, you can use the `cal_days_in_month` function. This function takes the year and the month as parameters and returns the number of days in that month. You can loop through all the months in a year to get the number of days for each month.

$year = date('Y');

for ($month = 1; $month <= 12; $month++) {
    $days_in_month = cal_days_in_month(CAL_GREGORIAN, $month, $year);
    echo "Number of days in month $month: $days_in_month\n";
}